package com.kanavi.stand.utils;

import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;

/**
 * @author tanghailan
 * @date 2020-10-22 13:53
 */
public class IpUtil {
    public static String getIpAddr(HttpServletRequest request) {
        String ipAddress = null;
        try {
            ipAddress = request.getHeader("x-forwarded-for");
            if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
                ipAddress = request.getHeader("Proxy-Client-IP");
            }
            if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
                ipAddress = request.getHeader("WL-Proxy-Client-IP");
            }
            if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
                ipAddress = request.getRemoteAddr();
                if (ipAddress.equals("127.0.0.1")) {
                    ipAddress = getHostAddress();
                }
            }
            // 对于通过多个代理的情况，第一个IP为客户端真实IP,多个IP按照','分割
            if (ipAddress != null && ipAddress.length() > 15) { // "***.***.***.***".length() == 15
                if (ipAddress.indexOf(",") > 0) {
                    ipAddress = ipAddress.substring(0, ipAddress.indexOf(","));
                }
            }

            // 解决请求和响应的IP一致且通过浏览器请求时，request.getRemoteAddr()为"0:0:0:0:0:0:0:1"
            if("0:0:0:0:0:0:0:1".equals(ipAddress)){
                ipAddress = getHostAddress();
            }
        } catch (Exception e) {
            ipAddress = "";
        }

        return ipAddress;
    }

    private static String getHostAddress(){
        // 根据网卡取本机配置的IP
        InetAddress inet = null;
        try {
            inet = InetAddress.getLocalHost();
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
        assert inet != null;
        return inet.getHostAddress();
    }

}
